Method for forming a structure with a hole

ABSTRACT

A method for forming a structure with a hole on a substrate is disclosed. The method may comprise: depositing a first structure on the substrate; etching a first part of the hole in the first structure; depositing a plug fill in the first part of the hole; depositing a second structure on top of the first structure; etching a second part of the hole substantially aligned with the first part of the hole in the second structure; and, etching the plug fill of the first part of the hole and thereby opening up the hole by dry etching. In this way 3-D NAND device may be provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 62/890,288 filed Aug. 22, 2019 titled METHOD FOR FORMING ASTRUCTURE WITH A HOLE, the disclosure of which is hereby incorporated byreference in its entirety.

FIELD OF INVENTION

The present disclosure generally relates to a method for forming astructure with a hole on a substrate. The method may include depositionof a sacrificial material and etching the material to achieve properformation of device structures for a 3-D NAND device.

BACKGROUND OF THE DISCLOSURE

NAND devices are logic gates usable in applications such as flashmemory, for example. Manufacture of the 3D NAND devices may includeformation of a hole in a structure disposed on a substrate. The hole maybe produced by making a first part of the hole in a first structurewhich first part of the hole then may be filled with a sacrificialmaterial. On top of the first structure a second structure may beprovided and a second part of the hole which is aligned with the firstpart of the hole may be provided. The hole may then be created byremoving the sacrificial material from the first part of the hole viathe second part of the hole.

An example of such a process for manufacturing a 3D NAND device may beillustrated in FIGS. 1A-1D. An intermediate product 100 for a 3D NANDdevice may be manufactured by a using a substrate 110 provided with astructure, for example a bilayer comprising a nitride layer 120 and anoxide layer 130. Deposition of the nitride layer 120 and the oxide layer130 may be repeated as needed to form a structure. As shown in FIG. 1A afirst structure e.g. a first stack 140 comprising alternating nitride120 and oxide layers 130 may be provided. Also a second structure e.g. asecond stack 150 comprising alternating nitride 120 and oxide layers 130may be provided.

The nitride layers 120 and the oxide layers 130 undergo a dry etchprocess to form a first part of a hole in the structure, as shown inFIG. 1B. FIG. 1C illustrates the intermediate product 100 for the NANDdevice after the dry etch and after undergoing a first process to form aliner, a second process to form a plug fill, and a third process topolish the surface. The first part of the hole 100 then comprises aliner 160 and a plug fill 170. The liner 160 may comprise silicon oxide(SiO_(x)), for example. After the third polishing process, additionaloxide-nitride layer stacks may be added on top of the stack 150, theliner 160, and the plug fill 170.

However, it may come to a point that after the first part of the hole isfilled with the liner 160 and the plug fill 170, the liner 160 and theplug fill 170 have to be removed. The plug fill 170 may be removed witha wet etch process. A wet clean process may follow to remove the liner(160). Due to capillary effects in the hole wet good etching of the plugfill may be difficult to achieve.

FIG. 1D illustrates the intermediate product 100 after removal tookplace. However, the chemistries may leave a residue 180 and cause damage190 to either the nitride layer 120 and/or the oxide layer 130 by thechemistries used for the removal of liner 160 or plug fill 170. Theresidue 180 and the damage 190 may render the NAND device unusable.Since the holes may become deeper and narrower with the next technologynodes it may be expected that the capillary effects of the wet etchliquid in the holes may increase and therefore good quality etching maybe more difficult to achieve. In addition, the removal of the liner 160and the plug fill 170 may be done with a slow etch rate, which meansthat the time to remove the liner 160 and the plug fill 170 may beundesirably long.

As a result, it is desired to achieve an improved apparatus and methodfor forming a structure with a hole on a substrate.

SUMMARY OF THE DISCLOSURE

This summary is provided to introduce a selection of concepts in asimplified form. These concepts are described in further detail in thedetailed description of example embodiments of the disclosure below.This summary is not intended to identify key features or essentialfeatures of the claimed subject matter, nor is it intended to be used tolimit the scope of the claimed subject matter.

In accordance with at least one embodiment of the invention, a method isdisclosed. An exemplary method comprises a method of forming a structurewith a hole on a substrate. The method may be for forming a 3-D NANDdevice. The method of forming a structure with a hole on a substrate maycomprise depositing a first structure on the substrate, etching a firstpart of the hole in the first structure and depositing a plug fill inthe first part of the hole. Subsequently, the method may continue bydepositing a second structure on top of the first structure, etching asecond part of the hole substantially aligned with the first part of thehole in the second structure; and, etching the plug fill of the firstpart of the hole and thereby opening up the hole. Etching the plug fillmay comprise dry etching.

These and other embodiments will become readily apparent to thoseskilled in the art from the following detailed description of certainembodiments having reference to the attached figures, the invention notbeing limited to any particular embodiment(s) disclosed.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

These and other features, aspects, and advantages of the inventiondisclosed herein are described below with reference to the drawings ofcertain embodiments, which are intended to illustrate and not to limitthe invention.

FIGS. 1A-1D are cross-sectional illustrations of intermediate productsfor a prior art process for forming a NAND device.

FIGS. 2A-2J are cross-sectional illustrations of an intermediate productfor a NAND device formed in accordance with at least one embodiment.

FIG. 3 is a process flow diagram in accordance with the embodiment.

FIG. 4 is a cross-sectional illustration of a NAND device formed inaccordance with the embodiment.

It will be appreciated that elements in the figures are illustrated forsimplicity and clarity and have not necessarily been drawn to scale. Forexample, the dimensions of some of the elements in the figures may beexaggerated relative to other elements to help improve understanding ofillustrated embodiments of the present disclosure.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Although certain embodiments and examples are disclosed below, it willbe understood by those in the art that the invention extends beyond thespecifically disclosed embodiments and/or uses of the invention andobvious modifications and equivalents thereof. Thus, it is intended thatthe scope of the invention disclosed should not be limited by theparticular disclosed embodiments described below.

The illustrations presented herein are not meant to be actual views ofany particular material, structure, or device, but are merely idealizedrepresentations that are used to describe embodiments of the disclosure.

Three-dimensional (3-D) Not-AND (NAND) devices may be utilized in memoryapplications. The manufacturing of 3-D NAND devices may compriseintermediate product structures comprising stacks of bilayers disposedon each other. The bilayers may comprise oxides and nitrides, forexample. When disposing stacks of multiple bilayers on other stacks,alignment and stresses on the layers and different features may becomecritical.

FIG. 2A illustrates an intermediate product 200 for a 3-D NAND device inaccordance with at least one embodiment. The intermediate product 200may comprise a substrate 210 and a first structure e.g. a first bilayerstack comprising a nitride layer 220 and an oxide layer 230. Thesubstrate 210 may comprise silicon, silicon oxide, or a metal oxide. Thenitride layer 220 may comprise at least one of: silicon nitride,germanium nitride, silicon germanium nitride (SiGeN), silicon oxynitride(SiON), germanium oxynitride (GeON), or combinations thereof. The oxidelayer 230 may comprise at least one of: silicon oxide, germanium oxide,silicon germanium oxide (SiGeOx), germanium oxynitride (GeON), siliconoxynitride (SiON), or combinations thereof. The deposition of thenitride layer 220 and the oxide layer 230 may be done in batch in areaction chamber of a vertical furnace. The method may thereforecomprise loading the substrate to a boat and moving the boat withsubstrates to a reaction chamber of a batch reactor of a verticalfurnace for processing.

The intermediate product 200 then may go through a dry etch process tocreate a first part of a hole in the first structure of the product 200as shown in FIG. 2B. The dry etch process may be anisotropic. The etchprocess may be accomplished with the aid of an etch mask created withlithography, for example. The dry etch process may utilize a halidechemistry with fluorine such as NF₃, CHF₃, SF₆, CF₄, C₂F₂ and theirmixtures, for example. The dry etch process may involve a plasma, forexample. The dry etch chemistry may involve oxygen or ozone in somecases.

Optionally, a first liner 240 may be added to the intermediate product200 afterwards as shown in FIG. 2C. The first liner 240 may comprise atleast one of a silicon, a germanium, a nitride and or an oxide. Forexample, the first liner may comprise silicon, silicon oxide, germaniumoxide germanium oxide, germanium, silicon germanium (SiGe), or germaniumnitride (GeN). Depositing the first liner 240 may comprise providing agermane precursor. The germanium precursor may be selected from germane,digermane, dichlorogermane, trichlorogermane, tetrachlorogermane,germanium alkoxide, or a combination thereof, for example. Thedepositing the first liner 240 may include flow of a silicon precursor.The silicon precursor may be selected from silane, disilane, trisilane,chlorosilane, dichlorosilane, trichlorosilane, tetrachlorosilane,methylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, or acombination of the above, for example.

The first liner 240 is illustrated to cover the tops and the sides (inthe first part of the hole) of the oxide layer 230 and the nitride layer220 of the first bilayer stack. The liner 240 may also extend to coveran exposed portion of the substrate 210 at the bottom of the hole. Theliner 240 may be deposited via an Atomic Layer Deposition (ALD) process,a Chemical Vapor Deposition (CVD) process, or an epitaxial process, forexample. The first liner may have a thickness smaller than 10,preferably 5 nanometer.

The first liner 240 may also act as a seed layer for subsequent layers.For example the seed layer may deposited by providing trisilane. Theseed layer may help improve the nucleation, quality and deposition ofthe subsequent plug fill. The seed layer may, for example, reduce theroughness.

FIG. 2D illustrates the result after a 3-D plug fill takes place. Theintermediate product 200 comprises a plug fill 250 in the first part ofthe hole in the structure. There may be remaining a void 260 in the plugfill 250. The void may be absent or may be closed with additionalprocess steps, for example with a heating step with a reflow of the plugfill material.

The plug fill 250 may comprise silicon germanium (SiGe). The plug fill250 may comprise graded germanium. The concentration of germanium in aSiGe plug fill 250 may range between 1% and 100%. The germanium contentmay be modulated for obtaining desirable material properties desired inthe subsequent process steps, such as removal rate in etch processes andthermal stability, for example. The concentration of germanium in theplug fill 250 may be increased from a first layer at the bottom and theside of the plug towards the center and the top of the plug by providingan increasing amount of germanium precursor.

The deposition of the liner 240 and/or the plug fill 250 may be done inbatch in a reaction chamber of a vertical furnace. The method maytherefore comprise loading the substrate to a boat and moving the boatwith substrates into a reaction chamber of the batch reactor of thevertical furnace for processing. The temperature window of thedeposition process may, for example be between 450 and 550° C., thedeposition rate may be between 5-20 nm/min with a Ge content between10-60 at % for the plug fill 250. The deposition of the liner 240 andthe plug fill 250 may be done in the same reactor in situ, so as tominimize the risk that the liner 240 may oxidize.

The shape of the plug fill 250 may be different as well as the size ofthe void 260 depending on the process used for the 3-D plug fill. As aresult of forming the void 260, the plug fill 250 may not completelyfill the hole. The void may result in a quicker removal during removalof the plug fill 250 later on in the process, thereby reducing thedevice damage by the etch chemistry and increasing throughput. On theother hand the void or pinch off may lead to an unstable fill andtherefore a lower quality of the fill and therefore may be unwanted. Thevoid 260 may therefore be substantially avoided in certain embodimentsof the invention.

The plug fill 250 may be formed through an in-situ process comprising adeposition step. The deposition step may occur by a thermal reaction, aplasma reaction, a plasma enhanced reaction, or a high density plasma(HDP) chemical vapor deposition (CVD) process. The deposition step mayinclude an etch back step involving for example a halide chemistry topartially open up the top of the plug fill and continuing depositionafterwards. The etch step may be a wet etch step or a dry etch step. Thehalide chemistry involved in the etch back step may comprise hydrogenfluoride (HF), hydrogen chloride (HCl), hydrogen bromide (HBr), or acombination of the above, for example. A dry etch process may involve aplasma, for example.

The deposition step may include flow of a silicon precursor such assilane, disilane, trisilane, chlorosilane, dichlorosilane,trichlorosilane, tetrachlorosilane, methylsilane, dimethylsilane,trimethylsilane, tetramethylsilane, or a combination of the above, forexample. The deposition step may also include a flow of a germaniumprecursor, such as germane, digermane, dichlorogermane,trichlorogermane, tetrachlorogermane, germanium alkoxide, or acombination of the above, for example. The ratio of germanium precursorvs silicon precursor during depositing of the silicon germanium plugfill 250 may be increased. The concentration of germanium in the silicongermanium plug fill 250 may therefore be increased from a first layer ofthe plug deposited on the bottom and the side of the first part of thehole towards the center and the top of the first part of the hole. Thedeposition step may involve an in-situ doping of germanium. For exampleby mixing germanium into a silicon precursor flow.

For a thermal deposition step, the pressure may range between 10 mTorrand 800 Torr, while the temperature may range between 50° C. and 800° C.For a plasma enhanced reaction or HDP CVD deposition step, the pressuremay range between 10 mTorr and 100 Torr, while the temperature may rangebetween 10° C. and 700° C.

The excess material of the plug fill 250 may be polished away, forexample, via a CMP process as shown in FIG. 2E. What is left over formsa first stack 270 of the first structure. Once there is a level surface,a second stack of the second structure may be formed on the liner 240and the plug fill 250.

The second structure e.g. a second bilayer stack 280 is shown in FIG.2F. The second stack 280, like the first stack 270, may comprises analternating arrangement of a nitride layer 220 and an oxide layer 230.The nitride layer 220 may comprise at least one of: silicon nitride,germanium nitride, silicon nitride, germanium nitride, silicon germaniumnitride (SiGeN), silicon oxynitride (SiON), germanium oxynitride (GeON),or combinations thereof. The oxide layer 230 may comprise at least oneof: silicon oxide, germanium oxide, silicon germanium oxide (SiGeOx),germanium oxynitride (GeON), silicon oxynitride (SiON), or combinationthereof. The deposition of the nitride layer 220 and the oxide layer 230may be done in batch in a reaction chamber of a vertical furnace. Themethod may therefore comprise loading the substrate to a boat and movingthe boat with substrates to a reaction chamber of a batch reactor of avertical furnace for processing.

A second part of the hole may then be formed in the second structuree.g. stack 280 via a dry etch process. The dry etch process may beanisotropic. The etch process may be accomplished with the aid of anetch mask created with lithography, for example. The dry etch processmay utilize a halide chemistry with fluorine such as NF₃, CHF₃, SF₆,CF₄, C₂F₂ and their mixtures, for example. The dry etch process mayinvolve a plasma, for example. The dry etch chemistry may involve oxygenor ozone in some cases. The liner 240 and the plug fill 250 may functionas an etch stop for the etch process. The liner 240 and the plug fill250 may remain left over after the etch process as shown in FIG. 2G andFIG. 2H.

Optionally, a second liner 245 may be added to the second structure e.g.stack 280 as shown in FIG. 2H. The second liner 245 may comprisesilicon, an oxide, a nitride and or a carbide layer. The second linermay for example comprise silicon oxy carbide nitride (SiOCN), aluminumnitride and/or boron carbide. Depositing the second liner thereforecomprises providing a nitrogen or oxide comprising reactant.

The second liner 245 may cover the tops and sides of the oxide layer 230and the nitride layer 220 bilayer stack of the second structure (in thesecond part of the hole). The second liner 245 may also extend to coveran exposed portion of the plug fill 250 (in the bottom of the secondpart of the hole). The second liner may be deposited in batch in areaction chamber of a vertical furnace. The method may thereforecomprise loading the substrate to a boat and moving the boat withsubstrates to a reaction chamber of a batch reactor of a verticalfurnace for processing. The second liner 245 may be deposited via anAtomic Layer Deposition (ALD) process, a Chemical Vapor Deposition (CVD)process, or an epitaxial process, for example. The second liner may havea thickness smaller than 10, preferably 5 nanometer.

The second liner 245 may be covering a portion of the plug fill 250 inthe bottom of the second part of the hole. The part of the second liner245 in the bottom of the second part of the hole may be removed with ananisotropic dry etch. For example with a reactive ion etch (ME).

The plug fill 250 may then be removed with a dry etch. The dry etch maybe isotropic. The etching may be accomplished in a reaction chamber of abatch reactor of a vertical furnace or in a reaction chamber of a singlewafer reactor.

When a furnace is used, the substrate 210 may be loaded to a boat havingspace to accommodate 25 to 250 substrates. The boat with substrates maybe moved into the reaction chamber of the reactor.

The batch or single wafer reactor may be constructed and arranged toprovide a gaseous etchant to the reaction chamber for isotropic etchingthe plug fill 250. For example, the reactor may be constructed toprovide one or more gaseous etchants comprising a halide to the reactionchamber. The halides may be selected from chlorides and fluorides. Thehalides may be selected from nitrogen trifluoride NF₃, chlorine Cl₂,hydrogen chloride (HCl); hydrogen fluoride (HF); hydrogen bromide (HBr);boron chloride (BCl₃); fluorine (F₂) for dry etching the plug fill 250.

The dry etch may be thermally activated. The temperature in the reactormay be kept below 500° C. to not harm temperature sensitive structuresin the intermediate product. The pressure in the reactor may be keptbelow 1 Torr. The reaction chamber may be kept substantially radicaland/or ion free. A suitable etchant at these temperatures may bechlorine Cl₂.

A dry etch with gaseous chlorine Cl₂ will not suffer from capillaryeffects in the hole as with a wet etch. A good etching of the plug fillmay therefore be achieved with a dry etch with gaseous chlorine Cl₂. Thedry etch may not leave a residue. Damage to either the nitride layer 220and/or the oxide layer 230 by the dry etch used for the removal may becircumvented. Using the thermally activated dry etch may be scalable sothat when the holes may become deeper and narrower with the nexttechnology nodes dry etch may still give the best etching. Thereactivity and therefor the etch speed but also the damage potential ofthe thermally activated dry etch may be carefully tuned by varying thetemperature in the reaction chamber.

The main time limiting factor for the dry etch may also be caused by thedepth and width of the holes created. The diffusion speed of thereactant and reaction by-products are determined by the depth and widthof the holes created. This limiting factor may be substantially the samefor a substrate processed in a batch reactor as for a single wafer(substrate) reactor and may become longer with future technology nodeswhere the holes may become narrower and deeper. Since only one substratemay be processed every time in a single wafer tool the throughoutpenalty caused by diffusion speed may be much larger in a single wafertool compared to a batch reactor where 25 to 175 substrates may beprocessed simultaneously. A batch reactor may therefore be preferred fordry etching the narrow holes.

The dry etch may substantially strip away the plug fill 250 comprisinggermanium at a faster rate than removing silicon. For example, athermally activated dry etch with Cl₂ of SiGe (50%) in the plug fill 250may result in an etch rate that is more than 1000 times higher than theetch rate of SiO/SiN used in the bilayers of the structures. Dry etchwith Cl₂ of SiGe (50%) in the plug fill 250 may result in an etch ratethat is more than 200 times higher than the etch rate of Si used in thefirst or second liners 240, 245.

The dry etch of SiGe with Cl₂ may be done at a temperature between 250and 450° C. and preferably between 300 and 400° C. At 350° C., forexample an high etch rate between 10 to 200 or 75-100 nm/minute may beachievable for the SiGe plug fil 250. The etch rate of the first andsecond silicon liner may be 0.1 to 2 or around 0.4 nm/min. under thesame circumstances. The first and second liners 240, 245 of Si maytherefore protect the first and second structures while the SiGe plugfill 250 is removed. The Si liners remain conformal over the first andsecond structures after the etch of the SiGe plug fill 250 minimizingthe risk on attacking the underlying first and second structures.

Etch rates of the plug fill 250 may range between 1 and 1000 nm/min.,between 10 and 100 nm/min., or between 1 and 10 nm/min. The first andsecond liner 240, 245 may protect the bilayers of the first and secondstructure during the dry etch.

After the plug fill 250 is removed and the optional first and secondliners are used, the first and second liners 240, 245 may still remain(see FIG. 2I). The first and second liners 240, 245 may then be removedvia an additional dry etch. The etching may also be accomplished withfor example a batch reactor of a vertical furnace or a single waferreactor. When a furnace is used, the substrate 210 may be provided to aboat having space to accommodate 25 to 250 substrates. The boat withsubstrates may be moved into a reaction chamber of the reactor. This maybe the same reactor as used for etching the plug fill 250.

The batch or single wafer reactor may be constructed and arranged toprovide a gaseous etchant to the reaction chamber for isotropic etchingthe first and second liners 240, 245. For example, the reactor may beconstructed to provide one or more gaseous etchants comprising a halideto the reaction chamber. The halide may be selected from nitrogentrifluoride NF₃, chlorine Cl₂, hydrogen chloride (HCl); hydrogenfluoride (HF); hydrogen bromide (HBr); boron chloride (BCl₃); fluorine(F₂) for dry etching the first liner 240.

The temperature in the reactor may be kept below 500° C., between 350and 500° C. and preferably between 375 and 450° C. and the pressure inthe reactor may be kept below 1 Torr. The reaction chamber may be keptsubstantially radical and/or ion free. The removal of the plug fill 250and the first and second liners may be done in situ in the same reactoror in the same tool to avoid oxidization when the product is transportedin a not controlled atmosphere (e.g. with oxygen or water in it).

The dry etch of the first or second liner may be done with Cl₂ at atemperature between 350 and 500° C. and preferably between 375 and 450°C. For example dry etch with Cl₂ of Si in the first and second liner240, 245 may result in an etch rate that is more than 10 times higherthan the etch rate of SiO/SiN used in the bilayers of the structures.The etch rate of the first and second liner if Si is used may be between0.1 to 10 or around 1 nm/min at 410° C. with Cl₂. So the plug fill 250may be dry etched at 350° C. until it is completely removed andsubsequently the first and second liner 240, 245 may be dry etched byincreasing the temperature to 410 or 420° C. The plug fill 250 and thefirst and second liner 240, 245 may therefore be dry etched in the samereaction chamber which improves the efficiency and cleanness of the etchprocess.

What remains is a structure combining the first and second structurewith the hole formed by the first and second hole part and forming theintermediate product 200 as shown in FIG. 2J. At this point, manufactureof the intermediate product 200 may be complete, or steps may berepeated in order to form additional structures e.g. stacks on top ofthe intermediate product 200.

FIG. 3 illustrates a method 300 for manufacturing a 3-D NAND device inaccordance with at least one embodiment of the invention. The method 300starts after a first structure has been deposited on a substrate tocreate an intermediate product. The intermediate product then isprocessed by: a dry etch step 310 with for example a plasma to create afirst part of the hole with an anisotropic etch; a first linerdeposition step 320; a plug fill step 330; a polishing step 340; asecond structure deposition step 350; a second dry etch step 360 withfor example a plasma to create a second part of the hole with ananisotropic etch; optionally and not depicted a second liner depositionstep; a plug fill dry etch step 370 (strip) with a gaseous etchant foran isotropic etch, and optionally and not depicted a first and secondliner dry etch step with also a gaseous etchant for an isotropic etch.The first and second liner dry etch step may not be needed if the plugfill dry etch 370 also removes the first and/or second liners or if nofirst or second liner is used. Steps 310-370 can be repeated, asillustrated by loop 380.

The methods of forming the 3-D NAND device may take place in an ALDreaction chamber, a chemical vapor deposition (CVD) chamber, anepitaxial reaction chamber, an etch reactor, a batch reaction chamber, amini-batch reaction chamber, or a single wafer reaction chamber, forexample. The proper reaction chamber may allow for all or a large partof these processes to occur as an in-situ process.

FIG. 4 illustrates a 3-D NAND device 400 made in accordance with atleast one embodiment of the invention. The 3-D NAND device 400 comprisesa substrate 410, an oxide-nitride layer stack section 420, a source line430, and a bit-line electrode section 440. The oxide-nitride layer stacksection 420 may also comprise a plurality of channel holes.

The particular implementations shown and described are illustrative ofthe invention and its best mode and are not intended to otherwise limitthe scope of the aspects and implementations in any way. Indeed, for thesake of brevity, conventional manufacturing, connection, preparation,and other functional aspects of the system may not be described indetail. Furthermore, the connecting lines shown in the various figuresare intended to represent exemplary functional relationships and/orphysical couplings between the various elements. Many alternative oradditional functional relationship or physical connections may bepresent in the practical system, and/or may be absent in someembodiments.

It is to be understood that the configurations and/or approachesdescribed herein are exemplary in nature, and that these specificembodiments or examples are not to be considered in a limiting sense,because numerous variations are possible. The specific routines ormethods described herein may represent one or more of any number ofprocessing strategies. Thus, the various acts illustrated may beperformed in the sequence illustrated, in other sequences, or omitted insome cases.

The subject matter of the present disclosure includes all novel andnonobvious combinations and subcombinations of the various processes,systems, and configurations, and other features, functions, acts, and/orproperties disclosed herein, as well as any and all equivalents thereof.

1. A method of forming a structure with a hole on a substrate, themethod comprising: depositing a first structure on the substrate;etching a first part of the hole in the first structure; depositing aplug fill in the first part of the hole; depositing a second structureon top of the first structure; etching a second part of the holesubstantially aligned with the first part of the hole in the secondstructure; and, etching the plug fill of the first part of the hole andthereby opening up the hole, wherein etching the plug fill comprises dryetching.
 2. The method of claim 1, wherein etching the plug fillcomprises providing the substrate to a reaction chamber constructed andarranged to provide a gaseous etchant for isotropic etching the plugfill in the reaction chamber.
 3. The method of claim 2, wherein etchingthe plug fill comprises providing one or more of the gaseous etchantscomprising a halide to the reaction chamber.
 4. The method of claim 3,wherein the halide is selected from the group consisting of nitrogentrifluoride (NF₃) and chlorine (Cl₂) for thermally activated etching theplug.
 5. The method of claim 2, wherein during etching the plug fill thetemperature in the reaction chamber is below 500° C. and the pressure inthe reactor is below 1 Torr and the reaction chamber is substantiallyradical and/or ion free.
 6. The method of claim 2, wherein the halide isselected from boron chloride (BCl₃); fluorine (F₂), fluoroform (CHF₃),sulfur hexafluoride (SF₆), tetrafluoromethane (CF₄) in the reactionchamber for dry etching the plug.
 7. The method according to claim 1,wherein the method comprises loading the substrate to a boat and movingthe boat with substrates to a batch reactor of a vertical furnace forprocessing.
 8. The method according to claim 1, wherein depositing theplug fill comprises providing a germanium precursor.
 9. The methodaccording to claim 8 wherein the germanium precursor comprise aprecursor selected from the group consisting of germane, digermane,dichlorogermane, trichlorogermane, tetrachlorogermane, germaniumalkoxide, and any combination thereof.
 10. The method according to claim8, wherein depositing the plug fill comprises providing a siliconprecursor and the plug fill comprises silicon germanium (SiGe) with agermanium content from 1% to 100%.
 11. The method according to claim 10,wherein the silicon precursor comprising a precursor selected from thegroup consisting of silane, disilane, trisilane, chlorosilane,dichlorosilane, trichlorosilane, tetrachlorosilane, methylsilane,dimethylsilane, trimethylsilane, tetramethylsilane, and any combinationthereof.
 12. The method according to claim 10, wherein a ratio ofgermanium to silicon is increased during depositing the silicongermanium to increase the germanium content in the silicon germaniumfrom a first layer of the plug towards the center and top of the plug.13. The method according to claim 1, wherein depositing the plug fillcomprises deposition steps with at least one etch step.
 14. The methodaccording to claim 1, wherein the method comprises: depositing a firstliner on top of the first structure and in the first part of the holebefore depositing a plug fill in the first part of the hole.
 15. Themethod according to claim 14, wherein the first liner comprises silicon,silicon oxide and/or germanium oxide.
 16. The method according to claim14, wherein depositing the first liner comprises providing a germaniumprecursor and the germanium precursor is selected from germane,digermane, dichlorogermane, trichlorogermane, tetrachlorogermane,germanium alkoxide, or a combination thereof.
 17. The method accordingto claim 14, wherein depositing the first liner comprises providing asilicon precursor wherein the silicon precursor comprises silane,disilane, trisilane, chlorosilane, dichlorosilane, trichlorosilane,tetrachlorosilane, methylsilane, dimethylsilane, trimethylsilane,tetramethylsilane, or any combination thereof.
 18. The method accordingto claim 1, wherein the method comprises: depositing a second liner ontop of the second structure and in the second part of the hole, etchingthe bottom of the second part of the hole and etching the plug fill ofthe first part of the hole.
 19. The method according to claim 18,wherein the second liner comprises silicon, an oxide, a nitride and/or acarbide.
 20. The method according to claim 19, wherein the second linercomprises silicon oxy carbide nitride (SiOCN), aluminum nitride and/orboron carbide.
 21. The method according to claim 20, wherein depositingthe second liner comprises providing a nitrogen or oxide comprisingreactant.
 22. The method according to claim 14, wherein depositing thefirst or second liner comprises depositing a liner with a thicknesssmaller than 10 nanometer.
 23. The method according to claim 14 whereinthe method comprises removing the first and/or second liner with a dryetch.
 24. The method of claim 23, wherein the method comprises providingthe substrate to a reaction chamber constructed and arranged to providea gaseous etchant for isotropic etching the first and/or second liner.25. The method of claim 24, wherein the method comprises providing oneor more of the gaseous etchants comprising a halide to the reactionchamber.
 26. The method of claim 25 wherein the halide is selected fromnitrogen trifluoride NF₃ and chlorine Cl₂, in the reaction chamber fordry etching the plug.
 27. The method of claim 24, wherein thetemperature in the reaction chamber is below 500° C. and the pressure inthe reaction chamber is below 1 Torr and the reaction chamber issubstantially radical and/or ion free.
 28. The method of claim 1,wherein etching the first or second part of the hole in the first orsecond structure comprises anisotropic etching.
 29. The method of claim1, wherein the method comprises polishing the plug fill beforedepositing the second structure on top of the first structure.
 30. Themethod of claim 1, wherein any of the above steps are repeated to form a3-D NAND device.
 31. The method of claim 1, wherein depositing a firstor second structure on the substrate comprising depositing a bilayerstructure on the substrate, the bilayer structure comprising alternatinglayers of a silicon oxide layer and a silicon nitride layer.
 32. Themethod according to claim 1, wherein the opening of the hole in thestructure has a width smaller than 200 nm.